The present invention generally relates to an anti-glare mirror used as a room mirror of a motor vehicle and having a prism mirror incorporated therein, and more particularly, to a tilting device for use in the anti-glare mirror, by which the prism mirror is automatically changed over between a normal position and an anti-glare position.
Conventionally, in room mirrors employed in motor vehicles and each provided with a prism mirror having a front face and a rear face acting as a reflecting surface, with a reflectance of the front face being smaller than that of the reflecting surface, it has been generally so arranged that, in the case where dazzling light rays from succeeding motor vehicles are reflected at night, etc. by the reflecting surface provided on the rear face of the prism mirror disposed at the normal position, the prism mirror is automatically tilted to the anti-glare position such that light rays reflected from the front face of the prism mirror are led towards eyes of a driver of the motor vehicle so as to free the driver from the dazzling light rays.
Conventionally, in tilting devices for use in the anti-glare mirrors of the above described type, it has been so arranged that two permanent magnets are secured to a rear face of a mirror mounting plate supported pivotally in a mirror casing, while two electromagnets are provided on the mirror casing so as to confront the two permanent magnets, respectively, whereby the prism mirror is pivoted to either one of a normal position and an anti-glare position through electromagnetic attraction and repulsion in response to electrical magnetization of the electromagnets.
However, the known tilting devices of the above described constructions have such an inconvenience that, in the case where the prism mirror is pivoted, a collision of the permanent magnet with the electromagnet through attraction therebetween produces a loud and harsh noise. Furthermore, the prior art tilting devices have such a disadvantage that, although a high precision is required for tilting angles of the prism mirror so as to minimize a positional difference between an image reflected by the prism mirror disposed at the normal position and an image reflected by the prism mirror disposed at the anti-glare position, it is quite difficult to obtain an accurate tilting angle thereof due to deviations in the dimensions of the permanent magnets, electromagnets, etc. during manufacture.